<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script type="text/javascript">
			function f1(){
				var btn1=document.querySelector("button")
				var txt=btn1.innerHTML
				txt="<b>"+txt+"</b>"
				btn1.innerHTML=txt
				
				var btn2=document.querySelector("button+button")
				var txt=btn2.innerText
				txt="<b>"+txt+"</b>"
				btn2.innerText=txt
			}
		</script>
	</head>
	<body>
		<button onclick="f1()">按钮1</button>
		<button onclick="f1()">按钮2</button>
	</body>
</html>
